The analysis comes after an explosive 2006 study by the University of Newcastle found Kooragang Island workers were up to three times more likely to be diagnosed with cancer than the rest of the population.

A subsequent review of the research by NSW Health, however, deemed that since the test group suffered from a number of unrelated cancers, their occurrence was probably coincidental.

International cancer expert professor Bruce Armstrong said since cancer was relatively common, groups of cancer cases occasionally occur by chance within small populations.

Subjects of the study were diagnosed with eight different cancers but Armstrong notes that different cancers are generally not caused by the same specific agent.

In coming to its conclusion, NSW Health held a series of meetings with the University of Newcastle research team.

Clarification was sought on the study method and analysis and additional analyses were requested and reviewed.